Decontamination of Gaseous Acetaldehyde over CoO x -Loaded SiO2 Xerogels under Ambient, Dark Conditions

• Published in: Langmuir Vol. 21; no. 6; pp. 2273 - 2280
• Main Authors: Martyanov, I. N, Uma, S, Rodrigues, S, Klabunde, K. J
• Format: Journal Article
• Language: English
• Published: American Chemical Society 15.03.2005
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la040070+

A series of CoO x -doped silica xerogels with various Co2+ loadings (Co/Si = 0, 1, 2, 4, 6, and 10 mol %) has been prepared. All xerogels exhibit large (800−1050 m2/g) surface areas. Narrow pore size distributions with pore size maxima around 3 nm are characteristic for Co/Si = 1, 2, 4, 6, 10 samples. As-prepared CoO x /SiO2 xerogels show high catalytic activity in the air oxidation of gaseous acetaldehyde at room temperature. Carbon dioxide and trace amounts of methane are the only products detected in the gas phase. Acetic acid, a less volatile product, resides on the surface of the xerogels but can slowly desorb. The formation of CO2 begins after an induction period. The beginning of CO2 production coincides with the conversion of Co2+ incorporated in the SiO2 framework into Co3+. Thermogravimetry/gas chromatography/mass spectrometry analysis, UV−vis and FTIR spectroscopies, as well as kinetic measurements are employed for CoO x /SiO2 catalyst characterization. A possible mechanism of the reaction is discussed.